1. Field
One or more embodiments of the present invention relate to a sound zoom operation involving changing a received sound signal according to a change in the distance from a near-field location to a far-field location, and more particularly, to a method, medium, and apparatus which can implement a sound zoom engaged with a motion picture zoom operation through the use of a zoom lens control in a portable terminal apparatus, for example, such as a video camera, a digital camcorder, and a camera phone supporting the motion picture zoom function.
2. Description of the Related Art
As video cameras, digital camcorders, and camera phones capable of capturing motion pictures are becoming increasingly more common, the amount of user created content (UCC) has dramatically increased. Similarly, with the development of high speed Internet and web technologies, the number of channels conveying such UCC is also increasing. Accordingly, there is also an increased desire for digital devices capable of obtaining a motion picture with high image and sound qualities according to the various needs of a user.
With regard to conventional motion picture photographing technologies, a zoom function for photographing an object at a far-field distance is applied only to the image of the object. Even when a motion picture photographing device photographs the far-field object, in terms of sound, the background interference sound at a near-field distance to the device is merely recorded as it, resulting in the addition of a sense of being audibly present with respect to the far-field object becomes impossible. Thus, in order to be able to photograph an object along with a sense of being present with respect to the far-field object, when sound is recorded along with the zoom function when capturing an image, a technology for recording the far-field sound by excluding the near-field background interference sound would be needed. Herein, in order to avoid confusion with a motion picture zoom function for photographing an object at a far-field distance, descriptions below regarding a technology to selectively obtain sound separated a particular distance from a sound recording device will be referred to as sound zoom.
In order to selectively obtain sound located a particular distance away from a recording device, there are techniques of changing a directivity of a microphone by mechanically moving the microphone along with the motion of a zoom lens and of electronically engaging an interference sound removal rate with the motion of a zoom lens. However, the former technique merely changes a degree of the directivity to the front side of microphone so that the near-field background interference sound cannot be removed. According to the latter technique, when the signal-to-noise ratio (SNR) of a far-field sound is low, it may be highly likely that a target signal is also removed due to a misinterpreting of a far-field target sound as the interference sound. In addition, in the engagement with a zoom lens control unit, the amount of removal of interference sound performed by an interference sound removal filter can be applied only to stationary interference sounds.